The present invention pertains generally to a process for the preparation of particulate (e.g., granular, powdered, flaked, etc.) detergent compositions by preparing a relatively high solids aqueous crutcher slurry containing surfactant, builder and, optionally, filler ingredients and subsequently drying same to produce the desired particulate detergent product. More particularly, the present invention pertains to such a process in which said crutcher slurry comprises at least about 0.1 weight percent of a glycoside surfactant on a total surfactant component weight basis.
In the manufacture of powdery or granular detergent compositions, it is common practice to prepare a relatively high solids aqueous crutcher slurry comprising a surfactant ingredient, a builder ingredient and water and to spray dry said crutcher slurry to form the desired powdery or granular detergent product.
When preparing a powdered or granular detergent product in the foregoing fashion, there is significant economic incentive to minimize the amount of water present in (and to maximize the dry solids content of) said crutcher slurry and to thereby reduce or minimize the amount of energy required in drying same to form the desired granular or powdered detergent product. Naturally, however, there are also practical upper limits within actual granular or powdered detergent manufacturing operations upon the maximum solids content which can be achieved while still providing a pumpable/sprayable slurry as well as upon the combinations of ingredients (e.g., surfactants, builders, etc.) suitable for preparing stable, homogeneous high solids aqueous crutcher slurries or suspensions. Thus, for example, while anionic surfactant-based crutcher slurries, are generally homogeneous, stable suspensions which are suitable for spray drying, they tend to become too viscous to handle at high solids levels (such as, for example, at solids levels in excess of 65 to 67 weight percent on a total weight basis).
On the other hand, at least certain types of builder/nonionic surfactant (e.g., ethoxylated fatty alcohol surfactants) combinations appear to generally be unsuitable for use in the above-indicated fashion by virtue of failing to provide a stable, homogeneously suspended crutcher slurry composition.
In view of the foregoing limitations of prior art systems, it would be high desirable to provide an improved process for preparing powdered or granular detergent compositions. In particular, it would be highly desirable to provide a means by which anionic surfactant-based crutcher slurry having increased solids content could be prepared without an attendant unacceptable increase in the viscosity of said slurry. Similarly, it would be quite desirable to provide a means to facilitate the preparation of a relatively high solids content nonionic surfactant-based crutcher slurry in stable, homogeneous form utilizing ingredients which do not normally provide stable, homogeneously suspended crutcher slurry compositions.
Prior attempts to overcome the aforementioned phase separation problem in nonionic surfactant-based crutcher slurries have included the incorporation of certain surface active iminodipropionate compounds as discussed in U.S. Pat. No. 4,416,792 to Blackstone (issued Nov. 22, 1983).
The problem of excessive viscosity in anionic surfactant-based crutcher slurries is addressed in U.S. Pat. No. 4,482,470 to Reuter et al (issued Nov. 13, 1984) by including within said crutcher slurry a small amount of a compound containing polyglycol ether groups specifically certain polyethylene glycols, certain polypropylene glycols and certain ethoxylated aliphatic alcohol or alkyl phenol compounds.
Another approach conventionally employed in the art is the use of sodium toluene (or xylene) sulfonate as a hydrotrope in detergent crutcher slurry compositions.